Everyone knows that a drop of blood or strand of hair is all the police need to identify suspect's DNA. But now scientists from Harvard have gone a step further: they can sequence an entire genome from a single cell.

The researchers have spent three years developing a new technology known as Multiple Annealing and Looping-based Amplification Cycles. As the name suggests, it allows them to duplicate the single DNA molecule present in a cell many times, which means a single cell provide more than enough to get the ball rolling. Xiaoliang Sunney Xie, one of the researchers, explains:

"If you give us a single human cell, we report to you 93 percent of the genome that contains three billion base pairs, and if there is a single base mutation, we can identify it with 70 percent detectability, with no false positives detected. This is a major development."

The research, published in Science, will allow doctors to fingerprint diseases like cancer in the future from just the tiniest scrap of tumor. That means they'll be able to work out tailored courses of treatment earlier, and keep cancer from spreading. That's a huge gain from such a singularly tiny source. [Harvard Gazette]